#!/bin/sh
# This script mounts USB mass storage devices when they are plugged in
# and unmounts them when they are removed.
# Copyright © 2004, 2005 Martin Dickopp
# Copyright © 2008, 2009, 2010 Rogério Theodoro de Brito
# Copyright © 2025, Jerry Vonau
#
# This file is free software; the copyright holder gives unlimited
# permission to copy and/or distribute it, with or without
# modifications, as long as this notice is preserved.
#
# This file is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY, to the extent permitted by law; without
# even the implied warranty of MERCHANTABILITY or FITNESS FOR A
# PARTICULAR PURPOSE.
# https://github.com/iiab/iiab/blob/master/roles/usb_lib/files/usbmount/copyright
# https://github.com/rbrito/usbmount/blob/master/debian/copyright
#set -e
exec > /dev/null 2>&1

######################################################################
# Auxiliary functions

# Log a string via the syslog facility.
log()
{
    if [ $1 != debug ] || expr "$VERBOSE" : "[yY]" > /dev/null; then
	logger -p user.$1 -t "usbmount[$$]" -- "$2"
    fi
}


# Test if the first parameter is in the list given by the second
# parameter.
in_list()
{
    for v in $2; do
	[ "$1" != "$v" ] || return 0
    done
    return 1
}


######################################################################
# Main program

# Default values for configuration variables.
ENABLED=1
MOUNTPOINTS=
FILESYSTEMS=
MOUNTOPTIONS=
FS_MOUNTOPTIONS=
VERBOSE=no

if [ -r /etc/usbmount/usbmount.conf ]; then
    . /etc/usbmount/usbmount.conf
    log debug "loaded usbmount configurations"
fi

if [ "${ENABLED:-1}" -eq 0 ]; then
    log info "usbmount is disabled, see /etc/usbmount/usbmount.conf"
    exit 0
fi

if [ ! -x /sbin/blkid ]; then
    log err "cannot execute /sbin/blkid"
    exit 1
fi

if [ "$1" = add ]; then

    # Per Policy 9.3.2, directories under /var/run have to be created
    # after every reboot.
    if [ ! -e /var/run/usbmount ]; then
        mkdir -p /var/run/usbmount
        log debug "creating /var/run/usbmount directory"
    else
        log debug "/var/run/usbmount exists"
    fi

    umask 022

    # Acquire lock.
    log debug "trying to acquire lock /var/run/usbmount/.mount.lock"
    lockfile-create --retry 6 /var/run/usbmount/.mount || \
	{ log err "cannot acquire lock /var/run/usbmount/.mount.lock"; exit 1; }
    trap '( lockfile-remove /var/run/usbmount/.mount )' 0
    log debug "acquired lock /var/run/usbmount/.mount.lock"

    # Grab device information from device and "divide it"
    #   FIXME: improvement: implement mounting by label (notice that labels
    #   can contain spaces, which makes things a little bit less comfortable).
    DEVINFO=$(/sbin/blkid -p $DEVNAME)
    FSTYPE=$(echo "$DEVINFO" | sed 's/.*[[:blank:]]TYPE="\([^"]*\)".*/\1/g; s/[[:blank:]]*//g;')
    UUID=$(echo "$DEVINFO"   | sed 's/.*[[:blank:]]UUID="\([^"]*\)".*/\1/g; s/[[:blank:]]*//g;')
    USAGE=$(echo "$DEVINFO"  | sed 's/.*[[:blank:]]USAGE="\([^"]*\)".*/\1/g; s/[[:blank:]]*//g;')

    if ! echo $USAGE | egrep -q "(filesystem|disklabel)"; then
        log debug "/$DEVNAME does not contain a filesystem or disklabel"
        lockfile-remove /var/run/usbmount/.mount
	    exit
    fi

    log debug "/$DEVNAME contains filesystem type $FSTYPE"
    BOOTFW_DEV=$(/usr/bin/findmnt -no source /boot/firmware)
    log debug "BOOTFW_DEV $BOOTFW_DEV"
    ROOT_DEV=$(/usr/bin/findmnt -no source /)
    log debug "ROOT_DEV $ROOT_DEV"
    BOOT_DEV=$(/usr/bin/findmnt -no source /boot)
    log debug "BOOT_DEV $BOOT_DEV"

    if [ $BOOTFW_DEV = /$DEVNAME ]; then
	    log debug "skipping BOOTFS_DEV $BOOTFS_DEV mounted at /boot/firmware"
        lockfile-remove /var/run/usbmount/.mount
        exit
    elif [ $ROOT_DEV = /$DEVNAME ]; then
        log debug "skipping ROOT_DEV $ROOT_DEV mounted at /"
        lockfile-remove /var/run/usbmount/.mount
        exit
    elif [ $BOOT_DEV = /$DEVNAME ]; then
        log debug "skipping BOOT_DEV $BOOT_DEV mount as /boot"
        lockfile-remove /var/run/usbmount/.mount
        exit
    fi

    # Try to use specifications in /etc/fstab to skip.
    if egrep -q "^[[:blank:]]*$DEVNAME" /etc/fstab; then
        log debug "skipping /$DEVNAME exit"
        lockfile-remove /var/run/usbmount/.mount
        exit
    elif grep -q "^[[:blank:]]*UUID=$UUID" /etc/fstab; then
        log debug "skipping $UUID"
        lockfile-remove /var/run/usbmount/.mount
	exit
    else
        log debug "/$DEVNAME contains filesystem type $FSTYPE"
        fstype=$FSTYPE
        # Test if the filesystem type is in the list of filesystem
        # types to mount.
        if in_list "$fstype" "$FILESYSTEMS"; then
            # Search an available mountpoint.
            for v in $MOUNTPOINTS; do
                if [ -d "$v" ] && ! grep -q "^[^ ][^ ]*  *$v " /proc/mounts; then
                    mountpoint="$v"
		            log debug "mountpoint $mountpoint is available for /$DEVNAME"
                    break
                fi
            done
            if [ -n "$mountpoint" ]; then
                # Determine mount options.
                options=
                for v in $FS_MOUNTOPTIONS; do
                    if expr "$v" : "-fstype=$fstype,."; then
                        options="$(echo "$v" | sed 's/^[^,]*,//')"
                        break
                    fi
                done
            if [ -n "$MOUNTOPTIONS" ]; then
                options="$MOUNTOPTIONS${options:+,$options}"
            fi

            # Mount the filesystem.
            log info "executing command: mount -t$fstype ${options:+-o$options} $DEVNAME $mountpoint"
            mount "-t$fstype" "${options:+-o$options}" "$DEVNAME" "$mountpoint"

            # Determine vendor and model.
            vendor=
            if [ -r "/sys$DEVPATH/device/vendor" ]; then
                vendor="`cat \"/sys$DEVPATH/device/vendor\"`"
            elif [ -r "/sys$DEVPATH/../device/vendor" ]; then
                vendor="`cat \"/sys$DEVPATH/../device/vendor\"`"
            elif [ -r "/sys$DEVPATH/device/../manufacturer" ]; then
                vendor="`cat \"/sys$DEVPATH/device/../manufacturer\"`"
            elif [ -r "/sys$DEVPATH/../device/../manufacturer" ]; then
                vendor="`cat \"/sys$DEVPATH/../device/../manufacturer\"`"
            fi
            vendor="$(echo "$vendor" | sed 's/^[[:blank:]]\+//; s/[[:blank:]]\+$//')"

            model=
            if [ -r "/sys$DEVPATH/device/model" ]; then
                model="`cat \"/sys$DEVPATH/device/model\"`"
            elif [ -r "/sys$DEVPATH/../device/model" ]; then
                model="`cat \"/sys$DEVPATH/../device/model\"`"
            elif [ -r "/sys$DEVPATH/device/../product" ]; then
                model="`cat \"/sys$DEVPATH/device/../product\"`"
            elif [ -r "/sys$DEVPATH/../device/../product" ]; then
                model="`cat \"/sys$DEVPATH/../device/../product\"`"
            fi
            model="$(echo "$model" | sed 's/^[[:blank:]]\+//; s/[[:blank:]]\+$//')"

            # Run hook scripts; ignore errors.
            export UM_DEVICE="$DEVNAME"
            export UM_MOUNTPOINT="$mountpoint"
            export UM_FILESYSTEM="$fstype"
            export UM_MOUNTOPTIONS="$options"
            export UM_VENDOR="$vendor"
            export UM_MODEL="$model"
            log info "executing command: run-parts /etc/usbmount/mount.d"
            run-parts /etc/usbmount/mount.d || :
        else
            # No suitable mount point found.
            log warning "no mountpoint found for $DEVNAME"
            exit 1
        fi
	fi
fi
elif [ "$1" = remove ]; then

    # A block or partition device has been removed.
    # Test if it is mounted.
    while read device mountpoint fstype remainder; do
    if [ "$DEVNAME" = "$device" ]; then
	    # If the mountpoint and filesystem type are maintained by
	    # this script, unmount the filesystem.
	    if in_list "$mountpoint" "$MOUNTPOINTS" &&
            in_list "$fstype" "$FILESYSTEMS"; then
            log info "executing command: umount -l $mountpoint"
            umount -l "$mountpoint"

            # Run hook scripts; ignore errors.
            export UM_DEVICE="$DEVNAME"
            export UM_MOUNTPOINT="$mountpoint"
            export UM_FILESYSTEM="$fstype"
            log info "executing command: run-parts /etc/usbmount/umount.d"
            run-parts /etc/usbmount/umount.d || :
        fi
        break
    fi
    done < /proc/mounts
else
    log err "unexpected: action '$1'"
    exit 1
fi

log debug "usbmount execution finished"
